The capital investment firm has built up its stake since last spring, spending 1.6 billion kronor ($220 million) to increase its capital holding from 4.9 percent to 6.6 percent. French firm Renault controls 21.8 percent of AB Volvo.
"They are a giant within capital investment, one of the biggest. They have acquired significant owner interests in other firms too. They have some ten percent stakes in other firms and now they hold six percent of AB Volvo. But for a big player it is a limited investment, it doesn't make much of a splash," said Mats Liss, a Swedbank share analyst, to news agency TT.
The firm underlined that this should not be seen as a power play from their side and more as an investment.
"We are long-term and invest in shares which we believe can develop well over a three-five year period," said Simon Levell at Capital Group in London to the Dagens Industri newspaper.
Following a decline in AB Volvo's share price last year by a half it has rebounded this year, up 36 percent to date. According to Mats Liss the purchase indicates that the trend is likely to continue.
"They have made that analysis and they usually do their homework thoroughly before making a move," Mats Liss said.